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प्रश्न
State two properties that a substance should possess when used as a thermionic emitter.
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उत्तर
Two properties are:
(i) High melting point. (ii) Low work function.
संबंधित प्रश्न
Answer the following questions based on a hot cathode ray tube.
What will happen to the beam when it passes through the electric field?
How can they be made to leave the metal surface? (State any two ways)
Name a gas caused by the Greenhouse effect
What is thermionic emission?
An electromagnetic radiation is used for photography in fog. [2]
(i) Identify the radiation.
(ii) Why is this radiation mentioned by you, ideal for this purpose ?
When is said to be the nucleus unstable?
Which part of the atom undergoes a change in the process of radioactive decay?
The half-life of a radioactive nuclide is 100 hours. The fraction of original activity that will remain after 150 hours would be ______.
A radioactive material decays by simultaneous emissions of two particles with half-lives of 1400 years and 700 years respectively. What will be the time after which one-third of the material remains? (Take In3 = 1.1)
Two radioactive sources A and B of half lives of 1 hour and 2 hours, respectively, initially contain the same number of radioactive atoms. At the end of two hours, their rates of disintegration are in the ratio of ______.
